JP2009169172A - Developing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a developing device that eliminates the need to reversely rotate a developer carrier, and relaxes fusion of toner on the doctor blade, and to provide a process cartridge equipped with this developing device, and to provide an image forming apparatus, etc. <P>SOLUTION: The two-component developing device for the image forming apparatus restricts developer, held on the developer carrier, by means of the doctor blade and develops a latent image on the image carrier by attaching developer after the restriction. Toner for use in this device is pulverized toner and a particle diameter per number of particles is 2.0 μm or less and content is 10 particle % or more. In the developing device with the toner state as such, the roughness of the surface of the doctor blade 29, by which upstream developer in the rotating direction of the developer carrier (28) is restricted, is predetermined to Ra=0.2 μm or less. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a developing device, more specifically, an image carrier on which an electrostatic latent image is formed, a developing device that visualizes the electrostatic latent image as a toner image, a process cartridge including the developing device, and image formation The present invention relates to a device and a method for defining the surface roughness of a regulating surface of a regulating member that regulates the developer.

  In general, in an electrophotographic image forming apparatus such as a copying machine, a printer, and a facsimile machine, an electrostatic latent image corresponding to image information is formed on an image carrier composed of a photosensitive drum or a photosensitive belt, and a developing device. Thus, a developing operation is executed to obtain a visible image. Thus, in the developing operation, in the developing device using the magnetic brush developing system using the two-component developer, the two-component developer is raised in a brush chain shape on the developer carrying member, and the development is performed in the developing region. The toner in the agent is supplied to the latent image portion on the latent image carrier. Here, the development region is a range where the magnetic brush rises on the developer carrier and is in contact with the image carrier.

  The developer carrying member is usually a sleeve (developing sleeve) formed in a cylindrical shape, and a magnet body (magnet roller) that forms a magnetic field so as to cause the developer to rise on the sleeve surface. In preparation. At the time of spike, the carrier spikes on the sleeve so as to follow the lines of magnetic force generated by the magnet roller, and charged toner is attached to the carrier related to the spike. The magnet roller includes a plurality of magnetic poles, and magnets for forming the magnetic poles are formed in a rod shape or the like. In particular, a developing main magnetic pole for raising a developer is provided in a developing region portion on the sleeve surface. When at least one of the sleeve and the magnet roller moves, the developer having raised the sleeve surface moves. A regulating member called a doctor blade that regulates the developer is attached so that the spikes by the developer are conveyed to and contact the image carrier at a uniform height, that is, a uniform amount.

  The developer transported to the development area is raised along the magnetic lines of force generated from the developing main magnetic pole, and the developer chain spikes are brought into contact with the surface of the latent image carrier so as to bend, and the developer chain spikes in contact with the developer chain. The toner is supplied (developed) while rubbing against the electrostatic latent image based on the relative linear velocity difference with the latent image carrier.

  Incidentally, toner fusion to the doctor blade becomes a problem, which may cause image problems. This is because the toner is fused to the doctor blade, so that further toner adheres to the fused toner or foreign matter in the developing device adheres to the developer carrier for regulating the developer. The gap with the doctor blade changes, the amount of developer regulation is not uniform, and image problems such as background stains (fogging) and vertical white spots due to low density occur. It has been found that such toner fusion to the doctor blade greatly affects the particle size of the toner. It is known that the toner that easily causes toner fusion to the doctor blade is a toner that contains a large amount of fine powder toner. The fine powder toner referred to here is a small particle toner having a particle diameter of 2.0 μm or less.

  Since the fine toner easily enters the concave and convex portions of the doctor blade and is easily affected by heat, the toner that enters the concave portion and stays on the surface of the doctor blade is melted by the heat of the doctor blade. When the toner on the surface of the doctor blade is melted and fused, toner, paper powder, and the like newly adhere to the toner blade, resulting in a large deposit. In other words, in order to prevent the toner from sticking to the doctor blade, it is known that the content of the small-diameter toner called fine powder should be reduced, but in the manufacturing process of the pulverized toner, the ultra fine powder toner is always produced. In order to reduce the content, a process of secondarily cutting fine powder is necessary. In order to cut this fine powder, the manufacturing time is extended and the cost is very high. Therefore, toner that is normally used tends to cause toner fusion to the doctor blade.

As a countermeasure against foreign matter adhering to the doctor blade by fusing toner to the doctor blade, a method of reversing the developer carrier has been proposed. In the method of reversing the developer carrying member, for example, after the developer carrying member is rotated forward and developed, the developer carrying member is reversed and the foreign matter such as the toner fixed to the doctor blade is peeled off.
In general, as shown in Patent Document 1, in order to regulate the developer layer thickness in a state where the doctor blade is in pressure contact with the developing roller in the one-component development method, the contact portion of the doctor blade with the developer is used. Although a technique for preventing fusion by defining a specific material is proposed, toner fusion is still likely to occur.
Further, as shown in Patent Document 2, the developing sleeve at the tip of the doctor blade is capable of smoothly regulating the layer thickness of the developer by a sufficient rectifying effect against the flow of the developer in the two-component developing system. A technique for defining the surface roughness of the facing surface is also proposed. However, this technique is only for the purpose of rectifying the developer and has a different purpose from this invention relating to toner fusion.
JP 2005-274756 A Japanese Patent No. 3696404

  Accordingly, the present invention solves the above-described conventional problems, and includes a developing device that can reduce the fusion of toner to a doctor blade without the need to reverse the developer carrier, and the developing device. It is an object to provide a process cartridge, an image forming apparatus, and the like.

  In order to solve the above-mentioned problems, the invention described in claim 1 is that the developer carried on the developer carrying member is regulated by a doctor blade, and the regulated developer is attached to the latent image on the image carrying member. A two-component developing device of an image forming apparatus for developing an image, wherein the toner to be used is a pulverized toner, and the number particle size is 2.0 μm or less and the content is 10% by number or more. The surface roughness of the surface on which the developer on the upstream side of the doctor blade is regulated with respect to the rotation direction of the body is defined as Ra = 0.2 μm or less.

  According to a second aspect of the present invention, in the developing device according to the first aspect, the material of the doctor blade is a non-magnetic metal material.

  According to a third aspect of the present invention, in the developing device according to the second aspect, the non-magnetic metal material is Al, and the surface thereof is anodized.

  According to a fourth aspect of the invention, there is provided the developing device according to any one of the first to third aspects, further comprising a toner recycling device that collects untransferred toner onto the transfer material and returns the toner to the developing device. To do.

  According to a fifth aspect of the present invention, an image forming apparatus includes an image carrier that forms an electrostatic latent image and a developing device that develops the electrostatic latent image to make it visible in one cartridge case. A process cartridge which is detachable from a main body, wherein the process cartridge includes the developing device according to any one of claims 1 to 4.

  According to a sixth aspect of the present invention, there is provided an image forming apparatus comprising: an image carrier that forms an electrostatic latent image; and a developing device that develops the electrostatic latent image to make it visible. Is provided with the developing device according to any one of claims 1 to 4.

  The invention according to claim 7 is the surface of the regulating member for regulating the developer carried on the developer carrying body, the surface regulating the developer on the upstream side in the developer transport direction of the developer carrying body. A method for determining roughness, wherein the developer is a pulverized toner, and the amount of the developer fixed to the regulating surface can be suppressed within a predetermined range based on a content ratio of the number particle size of 2.0 μm or less. The surface roughness is defined as follows.

  This invention is as described above. According to the invention described in claim 1, the developer carried on the developer carrying body is regulated by a doctor blade as a regulating member, and the regulated developer is regulated. A two-component developing device of an image forming apparatus for developing a latent image on an image carrier by adhering, wherein the toner used is a pulverized toner, and the number particle size is 2.0 μm or less and the content is 10% by number or more. In a certain developing device, since the surface roughness of the surface on which the developer on the upstream side of the doctor blade is regulated with respect to the rotation direction of the developer carrier is specified to be Ra = 0.2 μm or less, it has been difficult in the past. It has become possible to alleviate the adhesion of toner to the doctor blade. In addition, it is not necessary to reverse the developer carrier.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing a schematic configuration of a main part of a laser copying machine according to an embodiment. Reference numeral 10 in the drawing denotes a drum-shaped photoconductor that is an image carrier. Around the photoconductor 10, a roller-shaped charging device 11 provided on the side of the photoconductor 10 is sequentially developed in the rotational direction indicated by the arrow A of the photoconductor 10, the transfer device 13 and the paper separation device 14 are on the side, Is provided with a cleaning device 15. When making a copy, as is well known, an original is set on a contact glass (not shown), a copy switch is pressed, and an image of the original is read by an optical reader (not shown). A sheet (transfer material) P is fed into the space 13. On the other hand, the photosensitive member 10 rotates at a predetermined peripheral speed, and along with the rotation, the surface is uniformly charged by the charging device 11 that cleans with the cleaning pad 16, and the laser beam L from the optical writing device (not shown) is applied to the surface. Is written on the photosensitive member 10 to form an electrostatic latent image of the read original image. Subsequently, the toner adheres to the electrostatic latent image when passing through the position of the developing device 12, and the electrostatic latent image can be sequentially applied. Visualize. The toner image formed by making this visible image is transferred by the transfer device 13 onto the paper P conveyed between the photoreceptor 10 and the transfer device 13 as described above.

  After the transfer, the paper P is discharged by the paper separating device 14 and separated from the electrostatically adhering photoconductor 10 and conveyed to a fixing device (not shown) to fix the transferred image there. And discharge. A separation claw may be provided in place of the paper separation device 14 and mechanically separated from the photoreceptor 10. On the other hand, after the image is transferred, the photosensitive member 10 is cleaned by scraping off the residual toner remaining on the surface with a cleaning blade 17 provided in the cleaning device 15 and then neutralizing with a neutralizing lamp (not shown) to initialize the surface potential. To do.

  By the way, in the illustrated example, the above-described photoconductor 10, the charging device 11, the developing device 12, and the cleaning device 15 are provided in one cartridge case 19 to constitute a process cartridge 20. As shown in FIG. 2, the process cartridge 20 is detachable from the apparatus main body 18 of the copying machine (image forming apparatus) so that it can be taken in and out in the direction of the arrow from the front side.

  In such a process cartridge 20, the developing device 12 described above is configured by providing a developer accommodating portion 21 on the lower side and a developer carrying portion 22 on the upper side, as shown in FIG. The developer accommodating portion 21 is provided with a stirring member 23 that accommodates a dry two-component developer composed of a carrier and toner and conveys the developer while stirring. Although not shown, a toner concentration sensor for detecting the mixing ratio of the toner in the developer and the carrier is provided.

  On the other hand, the developer carrying portion 22 is provided with a developing sleeve (developer carrying body) 28 having a magnet inside at a position facing the photoconductor 10 through the developing window 27. Further, a doctor blade (developer regulating member) 29 that is a developing doctor for controlling the amount of developer supplied to the photoconductor 10 is provided. The cleaning device 15 provided on the photoconductor 10 includes a recovery blade 30 that scrapes up residual toner scraped off by the cleaning blade 17 in the cleaning case portion 19 a of the cartridge case 19, and a residue that is scraped up by the recovery blade 30. As shown in FIG. 3, a coil-shaped toner conveying member 31 that conveys the toner in the axial direction of the photoreceptor 10 is provided. Then, the toner collected by the cleaning device 15 is further fed into the process cartridge 20 through a conveying path formed by a pipe or the like, using a conveying member such as a screw, a coil, or a belt, or by using gravity, and developing the developing device 12. A toner recycling device 32 for returning to the agent storage unit 21 is provided.

  In the developing device 12, during copying, a driving motor (not shown) is driven to transmit the driving to rotate the developing sleeve 28, and the stirring member 23 is rotated to stir the developer, thereby frictionally charging the toner and the carrier. Then, it is conveyed to the developing sleeve 28. On the other hand, a predetermined bias is applied to the developing sleeve 28, and the toner in the developer is electrostatically attached to the surface of the photoreceptor 10, and the latent image on the surface is visualized. On the other hand, in the cleaning device 15, the rotation of the photosensitive member 10 is transmitted through a gear to rotate the toner conveying member 31, and the residual toner removed from the photosensitive member 10 is conveyed by the toner conveying member 31 to be cleaned. The toner is collected in the front side and returned to the developing device 12 by the toner recycling device 32.

  FIG. 4 shows an enlarged part of the developing device 12 provided in the process cartridge 20. As shown in FIG. 4, in the developing device 12 of the illustrated laser copying machine, the photosensitive member 10 that is an image carrier rotates in the A direction (counterclockwise in the figure), and the developing sleeve 28 that is a developer carrier is B. Rotate in the direction (clockwise in the figure). The tip of a doctor blade 29 that is a developer regulating member faces the developing sleeve 28. The doctor blade 29 is formed of a thin metal plate with its base end bent upward to have an L-shaped cross section, and is disposed horizontally along the axial direction of the developing sleeve 28, and both ends are supported by support plates (not shown). In the figure, 50 is an inlet seal bracket, 55 is a photoreceptor side inlet seal for preventing toner scattering from the developing sleeve 28, and 56 is a developing sleeve side inlet seal for preventing toner scattering from the developing sleeve 28. Both seals 55 and 56 are made of urethane.

FIG. 5 shows a simplified cross-sectional view of the developing sleeve 28 and the doctor blade 29.
(A) shows a state where the pumping amount of the developer 1 is regulated by the doctor blade 29 and an appropriate developer amount is being conveyed,
(B) shows a state in which the toner 2 adheres to the surface 29A where the developer 1 on the upstream side of the doctor blade is regulated with respect to the rotation direction of the developing sleeve of the doctor blade 29.
In this way, it can be seen that the amount of toner 2 that is fixed to the doctor blade 29 decreases so that the pumping amount of the developer 1 decreases only in the portion where the toner is fixed. As the pumping amount is reduced in this way, the amount of toner for development is reduced, the image density is lowered, and a phenomenon such as white stripes occurs. In addition, a phenomenon in which the background dirt (fogging) deteriorates due to a decrease in the scavenging power also occurs.

  Here, when a magnetic material is used as the material of the doctor blade 29, the developer 1 magnetized by the developing sleeve 28 adheres to the surface thereof, the flowability of the developer on the developing sleeve decreases, and the developer is removed. Easy to fix. Generally, as a usage of the doctor blade of the developing device, the magnetic doctor blade uses the magnetic force of the mag roller contained in the developing sleeve, so that it is used where the ears of the magnetic brush are relatively standing and the density is low. Therefore, the pressure on the doctor blade is small. On the other hand, the non-magnetic doctor blade is used in a portion where the ears of the magnetic brush are sleeping and the density is high in order to make the amount of the developer after passing through the doctor blade as uniform as possible. For this reason, the pressure on the doctor blade is large and it is easy to adhere to the doctor blade. In addition, depending on the manufacturing method, the metal material has a surface roughness due to the punching die and a streak in the direction perpendicular to the flow of the developer due to the extrusion of aluminum, so that the toner is liable to stay.

  Therefore, when using a non-magnetic doctor blade, measures are required to prevent toner sticking. As a countermeasure, it is effective to increase the slipperiness of the toner by reducing the surface roughness of the surface where the developer on the upstream side of the doctor blade is restricted. Further, it is necessary that the surface of the cutting part at the tip of the doctor blade does not cause wear due to contact with a hard component in the developer even when used for a long time. Considering these things, the doctor blade is made of a non-magnetic material and has to have a sufficient surface hardness. Therefore, a non-magnetic metal material such as Al, Cu, SUS304, SUS316L, SUSXM7 or the like was used for the doctor blade. However, the Al doctor blade has a low surface hardness and a Vickers hardness of HV 60 to 70. It is easy to wear at this hardness. Therefore, if the surface is made of Al only, the surface hardness becomes HV200 or more in terms of Vickers hardness by treating the surface with anodizing, and it becomes possible to prevent wear.

FIG. 6 shows the relationship between the sheet passing time and the developing doctor temperature in the sheet passing mode. The paper passing time is 8 hours.
In (1), the paper was passed continuously for 8 hours, and it was found that the developing doctor temperature was about 48 ° C. and saturated.
(2) is a repetition of the sheet passing mode in which after five sheets are continuously passed, a 10-second rest interval is taken. At this time, it turns out that the temperature of a doctor blade rises slowly and is saturated at about 38 degreeC.
By the way, the time required to pass 1000 sheets continuously is about 20 minutes. FIG. 7 shows the result of confirming whether or not there is a thin density (vertical white spot) generated in the halftone or black solid image generated by the doctor blade fixing in every 1000 image samples at this time.

  From this result, it can be seen that a low density occurs only when continuous paper feeding is performed. Observation of the doctor blade revealed that a large amount of toner had adhered. When the adhered foreign matter was analyzed, paper dust and toner were detected. Further, when the portion that becomes the core of fixation on the doctor blade surface was analyzed, a large amount of wax as a toner component was detected. This is considered to be a fused state melted due to heat applied to the toner. Incidentally, the toner used at this time is pulverized toner. The ground toner tends to be wax-rich on the toner surface. Since the wax melts faster than the resin, if it is on the toner surface, it will first melt and fuse. On the other hand, the toner prepared by the polymerization method contains wax and does not come out on the surface, so that it is difficult to weld and does not cause a problem.

  From this, it was found that the state where the toner fusion to the doctor blade is likely to occur is a state where the temperature of the doctor blade is high. The temperature of the developing doctor is most severe when the paper is continuously fed. It has been found that when the toner is fused to the doctor blade, foreign particles such as another toner and paper powder adhere to the softened toner and grow into a large toner lump.

  The fusion to the doctor blade occurs on the surface where the developer on the upstream side of the doctor blade is restricted with respect to the rotation direction of the developing sleeve. It was considered that if the toner was constantly moving on the surface of the doctor blade, it was less affected by the heat of the doctor blade, and if the toner remained at the same position on the surface, it was affected by the heat and the toner was dissolved.

  FIG. 8 shows the developing sleeve after passing the paper in the continuous mode according to the surface roughness of the surface where the developer on the upstream side of the doctor blade is regulated with respect to the rotation direction of the developing sleeve in the doctor blade. It is the result of having measured the gap of a doctor blade. The initial set value is 0.38 mm. The number of sheets passed was 15000 sheets (5 hours), and continuous sheets were passed. As a result, it can be seen that the rougher the surface roughness, the larger the toner fixing amount and the narrower the gap.

  FIG. 9 is an evaluation of background dirt (fogging) from the image at that time. It can be seen that the doctor blade having a rough surface has a large amount of toner adhering and a narrow gap, so that the scavenging force to the photosensitive member is reduced and the background stain (fogging) is deteriorated. Therefore, by reducing the surface roughness, the slipping property is improved, and the toner is easy to move on the doctor blade. Therefore, the toner is hardly affected by heat and the toner welding can be reduced.

  It has been found that the level of such toner fusion varies greatly depending on the amount of fine powder of toner. It has also been found that it is not related to the average particle size. The toner used in the data of FIGS. 8 and 9 is a result when three types of toners having a toner volume average particle size of 4.9 μm and different number particle sizes of 2.0 μm or less are used. FIG. 8 shows that when the number particle size is 2.0 μm or less, the gap between the doctor blade and the developing sleeve does not change, and the occurrence of toner fusion is small. Further, even when the number particle size is 2.0 μm or less and the content is 10% by number or more, toner fusion can be prevented by setting the surface roughness of the doctor blade surface to 0.2 μm or less. As a result, as shown in FIG. 9, it was found that the problem of background dirt (fogging) was also solved. That is, in order to prevent the toner from adhering to the doctor blade, the content ratio of the number particle size of 2.0 μm or less called ultrafine powder may be set to 10 number% or less.

  As shown in FIG. 10, the same evaluation was performed with toners having a volume average particle diameter of 4.9 μm, 5.9 μm, and 6.8 μm, but it was found that toner welding does not affect the volume average particle diameter. That is, it can be seen from this result that the problem of toner welding is greatly related to the amount of toner called ultrafine powder. The toner having an average particle size of 5.9 μm has a reduced amount of ultrafine powder because it has undergone a process of cutting the ultrafine powder toner. As the toner particle size becomes smaller, it is considered that the toner easily enters the concave portion of the doctor blade, the toner stays, is affected by heat, and is easily welded. From this result, it was found that toner welding can be prevented by defining the surface roughness of the doctor blade in accordance with the content of toner called ultra fine powder.

  This is apparent from the particle size distribution as shown in FIG. This is the particle size distribution of the toner used in FIG. Looking at the particle size distribution, it can be seen that the three are completely different. The toner having a large amount of super fine powder of 2.0 μm or less (denoted by A), which is a problem, is a toner fused. Even if the volume average particle size is large, it is found that if there is a large amount of fine powder, the toner is easily fused, and if the volume average particle size is small, if the amount of fine powder is small, it is found that the toner is difficult to fuse.

  Here, the measurement of the ultrafine toner expressed by the number particle size is specified. Ultra fine toner is measured using a flow type particle image analyzer (“FPIA-2100”; manufactured by Sysmex Corporation), and analyzed using analysis software (FPIA-2100 Data Processing Program for FPIA version 00-10). It was. Specifically, 0.1 to 0.5 ml of 10 wt% surfactant (alkylbenzene sulfonate Neogen SC-A; manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is added to a glass 100 ml beaker, and each toner 0.1 to 0 is added. 0.5 g was added and stirred with a microspatel, and then 80 ml of ion-exchanged water was added. The obtained dispersion was subjected to a dispersion treatment for 3 minutes with an ultrasonic disperser (manufactured by Honda Electronics Co., Ltd.). The shape and distribution of the toner were measured using the FPIA-2100 until the density of the dispersion was 5000 to 15000 / μl. In this measurement method, it is important that the concentration of the dispersion liquid is 5000 to 15000 / μl from the viewpoint of measurement reproducibility of the average circularity. In order to obtain the dispersion concentration, it is necessary to change the conditions of the dispersion, that is, the amount of surfactant to be added and the amount of toner. The amount of the surfactant varies depending on the hydrophobicity of the toner as in the measurement of the toner particle diameter described above. If a large amount is added, noise due to bubbles occurs. It becomes insufficient. Further, the toner addition amount differs from the particle size, and is small when the particle size is small and needs to be increased when the particle size is large. When the toner particle size is 3 to 7 μm, the toner amount is 0.1 to 0. By adding 0.5 g, the dispersion concentration can be adjusted to 5000 to 15000 / μl.

FIG. 12 explains the difference in toner fixation depending on the surface roughness of the doctor blade.
(1) is when a doctor blade having a surface roughness Ra = 0.2 μm is used. Even fine powder toner that tends to enter the recesses of the doctor blade is difficult to fuse because the recesses are small and cannot enter, so the toner always flows without staying on the doctor blade surface.
(2) shows a case where a doctor blade having a surface roughness Ra = 0.4 μm is used, but it can be seen that the fine toner stays in the recess. The figure is shown in order of time by arrows, but the toner staying on the surface melts under the influence of the heat of the doctor blade. Here, the wax component of the toner starts to melt first. Another toner adheres to the melted and soft toner and stays there. The staying toner melts in the same manner, and this process is repeated to increase the fixed toner layer. In addition, paper recycling such as paper fibers and additives in the developer tends to adhere to the softened toner by toner recycling, and the fixed matter becomes larger by attaching paper powder. Toner recycling It can be seen that problems are likely to occur in the image forming apparatus having the apparatus. Therefore, in an image forming apparatus having a toner recycling device, by defining the surface roughness of the surface on which the developer on the upstream side of the doctor blade is regulated, toner fusion is unlikely to occur, and image problems and the like are unlikely to occur. A forming apparatus can be provided.

  In addition, the said embodiment showed only a preferable example, and this invention is not limited to illustrated embodiment. The specific configuration of the charging device 11, the developing device 12, the cleaning device 15, and the process cartridge 20 constituted by each of these devices and the photoreceptor 10 is also an example, and can be arbitrarily changed as long as it is within the scope of the claims. Needless to say, this can be done.

Next, the specific effects of the invention described in claim 2 and the following claims will be described.
According to the second aspect of the present invention, since the doctor blade is made of a non-magnetic metal material, the toner fusion to the doctor blade can be relaxed even under the condition where the toner is easily fused. . According to the invention described in claim 3, since the non-magnetic metal material is Al and the surface thereof is anodized, it is possible to increase the hardness of the doctor blade surface and make it difficult to wear. . According to the fourth aspect of the present invention, since the toner recycling device that collects the toner that has not been transferred to the transfer material and returns it to the developing device is provided, there is a large amount of foreign matter such as paper dust, and there is fused toner. Even in a developing device in which foreign matter is attached and the toner lump tends to become large, it is possible to alleviate toner fusion to the doctor blade. According to the fifth aspect of the present invention, it is possible to provide a process cartridge having the same effects as those of the first to fourth aspects and having no image problem due to toner fusion to the doctor blade. According to the sixth aspect of the present invention, it is possible to provide an image forming apparatus having the same effects as those of the first to fourth aspects and having no image problem due to toner fusion to the doctor blade. According to the seventh aspect of the invention, the effect that the toner fusion to the regulating member can be relaxed can be obtained, and the image problem due to the toner fusion can be eliminated.

It is a schematic block diagram of the principal part of the laser copying machine which is one embodiment of this invention. FIG. 2 is a perspective view showing a state in which the process cartridge is taken in and out of the image forming apparatus main body. It is a perspective view which shows a toner recycling apparatus same as the above. It is a principal part enlarged view which shows the periphery of a developing sleeve and a doctor blade. (A) is a state where the pumping amount of the developer is regulated by the doctor blade and the proper amount of developer is being conveyed, and (B) is a state where the foreign matter adheres to the doctor blade and the amount of developer is properly conveyed. It is explanatory drawing which shows each which is not. (1) is a drawing showing a relationship between a sheet passing time and a developing doctor temperature in a continuous sheet passing mode and (2) is an intermittent sheet passing mode. It is a chart showing an abnormal image occurrence situation for each sheet passing mode. 6 is a graph showing the relationship between the surface roughness of the doctor blade and the developing sleeve = doctor blade gap (after passing 15000 sheets). It is a graph which shows the relationship (after passing 15000 sheets) of the surface roughness of a doctor blade and image background stain | pollution | contamination (fogging). It is a chart which shows the background dirt (cover) result according to volume average particle diameter. 3 is a graph showing the particle size distribution of an evaluated toner. FIG. 7 is an explanatory diagram of toner fixation according to a difference in doctor blade surface roughness.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Developer 2 Toner 10 Photoconductor (image carrier)
DESCRIPTION OF SYMBOLS 11 Charging device 12 Developing device 13 Transfer device 14 Paper separating device 15 Cleaning device 18 Main body 19 Cartridge case 20 Process cartridge 28 Developing sleeve (developer carrier)
29 Doctor blade (developer regulating member)
32 Toner recycling device

Claims (7)

  A two-component developing device of an image forming apparatus that regulates a developer carried on a developer carrying body with a doctor blade and attaches the regulated developer to develop a latent image on the image carrying body. In the developing device in which the toner to be ground is a pulverized toner and the number particle size is 2.0 μm or less and the content is 10% by number or more, the developer on the upstream side of the doctor blade with respect to the rotation direction of the developer carrier is A developing device characterized in that the surface roughness of the regulated surface is specified to be Ra = 0.2 μm or less.   2. The developing device according to claim 1, wherein the doctor blade is made of a non-magnetic metal material.   3. The developing device according to claim 2, wherein the non-magnetic metal material is Al and the surface thereof is anodized.   4. The developing device according to claim 1, further comprising a toner recycling device that collects toner that has not been transferred to the transfer material and returns the toner to the developing device.   An image carrier that forms an electrostatic latent image and a developing device that develops the electrostatic latent image to make it visible in one cartridge case, and is a process cartridge that is detachable from the image forming apparatus main body. The process cartridge according to claim 1, comprising the developing device according to claim 1.   5. An image forming apparatus comprising: an image carrier that forms an electrostatic latent image; and a developing device that develops the electrostatic latent image to make it visible. The image forming apparatus is any one of claims 1 to 4. An image forming apparatus comprising the above developing device.   A regulating member for regulating the developer carried on the developer carrying body, a method for defining the surface roughness of the surface regulating the developer on the upstream side in the developer transport direction of the developer carrying body, The developer is a pulverized toner, and the surface roughness is defined based on the number particle size of 2.0 μm or less so that the amount of the developer fixed to the regulating surface can be suppressed within a predetermined range. A defining method characterized by that.

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